package TestDemo;

class A {
    public int a;
}

class B extends A {
    public int b;
}

class C extends B {
    public int c;
}

public class TestDemo3 {
    public static void main(String[] args) {
        A a1 = new A();
        A a2 = new B();
        A a3 = new C();
    }
}
